1. Field of the Invention
This invention relates to an electronic gas lighter which utilizes a cell or a piezoelectric element for ignition, and more particularly to an electronic gas lighter having a fuel tank made of plastics and an ignition device mounted on the fuel tank.
2. Description of the Prior Art
There has been in wide use a disposable gas lighter having a plastic fuel tank on which an ignition device is mounted. However, most of the currently available disposable gas lighters having a plastic fuel tank utilize a file wheel and a flint as the ignition device, and disposable electronic gas lighters in which electric discharge spark is used for ignition are not in wide use at present. In this specification, the term "disposable gas lighter" generally refers to an inexpensive gas lighter having a plastic fuel tank irrespective of whether or not it is rechargeable.
One significant difficulty encountered in realizing a disposable electronic gas lighter is providing reliable ignition. That is, the duration of spark discharge used in the electronic gas lighter is very short (15 to 30.mu.), and therefore fuel cannot be surely ignited unless it is mixed with a sufficient amount of air. Accordingly, the windshield must be provided with a vent opening to feed a sufficient amount of fresh air to the region near the fuel outlet nozzle in which spark discharge is generated.
However, when a sufficient amount of air is fed to the region, fuel burns in the space within the windshield to heat the windshield and the overheated windshield softens and deforms the plastic body or the plastic fuel tank supporting the windshield.
There has been proposed a disposable gas lighter having a plastic body in which a flame orifice cap having a flame orifice is provided above the fuel outlet nozzle so that fuel burns above the flame orifice. However, this solution cannot be directly applied to the electronic gas lighter due to the need to provide reliable ignition as described above.
Thus, in order to realize a practical disposable electronic gas lighter, both of two conflicting demands must be met at least sufficiently for practical use.